Black Iron Pipe Nipples (Domestic)

Domestic black iron pipe nipples are short, male-threaded carbon steel pipe sections used to join two female-threaded fittings in gas supply, steam, and hydronic heating systems. SupplyHouse carries domestic black iron pipe nipples from Anvil and Ward, two of the most recognized names in domestic pipe nipple production. Ward black domestic fittings are now sold under the Anvil brand following ASC Engineered Solutions' acquisition of Ward. The lineup runs from small-diameter close nipples in 1/8" all the way through larger standard-length nipples, with right and left nipple options for repair work where the run can't be broken. For contractors who specify domestic on every gas or steam job, black iron pipe nipples from Anvil and Ward cover the sizes and configurations that come up most.

KEY SUBCATEGORIES / PRODUCT TYPES

Standard Length Black Iron Pipe Nipples (Anvil) Standard length domestic black iron pipe nipples from Anvil are the everyday workhorse of the category. SKU 0330021205 covers the perennially useful 3/4" x 6" size. SKU 0330016601 is a 1/2" x 6-1/2" nipple, described on its SupplyHouse listing as a Standard Black Schedule 40 Nipple (Domestic). SKU 0330025800 extends the lineup into 1" diameter at 6-1/2" length for larger-bore gas and steam connections. SKU 0330046608 handles the 3" x 6" size for heavier commercial and industrial runs. All carry NPT taper pipe threads on both ends and conform to ASTM A733.

Close Nipples (Anvil) Close nipples are domestic black iron pipe nipples with no unthreaded center section, designed for installations where fittings need to connect with virtually no exposed pipe between them. SKU 0330005000 is the 1/4" close nipple. SKU 0330028200 covers 1-1/4" close, a common size in residential steam and gas distribution. Close nipples are the right call when clearances are genuinely tight and a standard nipple won't fit the gap. Per their listings, Ward black domestic close nipples are now sold under the Anvil brand.

Short-Run Nipples (Anvil) Short-run domestic black iron pipe nipples fill the 1-1/2" to 4" length range that handles most fitting-to-fitting connections on gas drops, boiler headers, and hydronic distribution. SKU 0330000803 covers 1/8" x 2", a staple for gauge connections and small-bore gas taps. SKU 0330005802 covers 1/4" x 2-1/2". SKU 0330028606 covers 1-1/4" x 2-1/2". SKU 0330042003 covers 2-1/2" x 4-1/2" for larger headers. All are domestic Anvil production with NPT threads and Schedule 40 wall thickness.

Right and Left Nipples (Ward) Right and left domestic black iron pipe nipples carry one right-hand NPT thread and one left-hand NPT thread, one on each end. Tightening the nipple in place drives both connections simultaneously, making right and left nipples the repair solution when the run can't be rotated. SKU 01RL04040 is the 1/2" x 4" right and left black nipple from Ward. SKU 01RL06040 is the 3/4" x 4" right and left black nipple from Ward. Both are listed as in-stock domestic nipples on SupplyHouse.

BUYING GUIDE / HOW TO CHOOSE

The first decision when specifying domestic black iron pipe nipples is nominal pipe size. Nominal size doesn't equal outer diameter. A 3/4" nipple measures 1.050" OD. Match the nipple's nominal size to the nominal size of the fittings on both ends, not to a measured pipe dimension.

Length comes next. Close nipples like SKU 0330005000 and SKU 0330028200 are for tight spaces with no room for exposed pipe. Short-run nipples in the 2" to 4" range, like SKU 0330000803 and SKU 0330028606, cover most standard fitting-to-fitting connections on gas drops and boiler piping. Longer nipples in the 6" to 6-1/2" range, like SKU 0330021205 and SKU 0330025800, work where the run spans a larger gap between fittings.

For repair work on existing threaded systems where breaking the full run isn't practical, right and left nipples like SKU 01RL04040 (1/2" x 4") and SKU 01RL06040 (3/4" x 4") let the repair tighten into place from the center without disturbing either end of the connection.

On the domestic vs. imported question: Ward black domestic fittings now fall under the Anvil brand following ASC Engineered Solutions' acquisition of Ward. Domestic production typically carries domestic mill traceability. For jobs with specification requirements calling for domestic material certification, Anvil's domestically manufactured black iron pipe nipples cover that requirement.

One firm application boundary: domestic black iron pipe nipples are not suitable for potable water supply lines. Black iron's manufacturing residue can discolor water. The correct applications are natural gas supply, steam, and hydronic heating.

FAQs

What sizes of domestic black iron pipe nipples are carried at SupplyHouse?

SupplyHouse carries domestic black iron pipe nipples from Anvil and Ward across a range of diameters and lengths. Confirmed sizes include 1/8" (SKU 0330000803), 1/4" (SKU 0330005802), 1/2" (SKU 0330016601), 3/4" (SKU 0330021205), 1" (SKU 0330025800), 1-1/4" (SKU 0330028606), 2-1/2" (SKU 0330042003), and 3" (SKU 0330046608), with close nipple options including SKU 0330005000 and SKU 0330028200. Ward black domestic fittings are now sold under the Anvil brand following the ASC Engineered Solutions acquisition.

What is a right and left black iron pipe nipple, and when is one needed?

A right and left black iron pipe nipple is a domestic nipple with one right-hand NPT thread on one end and one left-hand NPT thread on the other. Turning the nipple clockwise tightens both ends simultaneously, which makes it the right tool for repairing a threaded run where neither end can be rotated. SKU 01RL04040 (1/2" x 4") and SKU 01RL06040 (3/4" x 4") are the Ward right and left nipples listed at SupplyHouse for those common sizes.

What's the difference between a close nipple and a standard domestic black iron pipe nipple?

The difference between a close nipple and a standard domestic black iron pipe nipple is the center section. A standard nipple has an unthreaded center section between the two NPT ends. A close nipple carries threads end to end with no bare center steel exposed when fully engaged. SKU 0330005000 (1/4" close) and SKU 0330028200 (1-1/4" close) are Anvil close nipples at SupplyHouse for applications where clearance between fittings is minimal.

Are Ward domestic black iron pipe nipples still available?

Ward black domestic fittings are now sold under the Anvil brand. Anvil's parent company, ASC Engineered Solutions, acquired Ward, and Ward domestic production carries forward under the Anvil name. Right and left nipples like SKU 01RL04040 and SKU 01RL06040 are still listed under the Ward brand on SupplyHouse, while standard and close nipples from that same domestic production now appear under the Anvil brand.

Can domestic black iron pipe nipples be used for natural gas lines?

Domestic black iron pipe nipples are a standard, widely accepted material for natural gas supply lines in residential and commercial applications. Anvil domestic black iron pipe nipples like SKU 0330021205 (3/4" x 6") and SKU 0330016601 (1/2" x 6-1/2") are Schedule 40 welded carbon steel with NPT threads, the configuration used in gas piping throughout the trades. Black iron pipe nipples aren't suitable for potable water supply; galvanized or approved plastic materials are the correct choice for water lines.